The lack of federal regulation and the decreased cost to both consumers and service providers has lead to a rise in the popularity of digital telephones that enable callers to conduct telephone calls connected over a digital network such as the Internet. Such digital telephones utilize digital telephony packets containing both the signaling information and actual voice data necessary to establish and conduct a telephone call. The most popular protocol for conducting such telephone calls over a network such as the Internet is the Voice over IP protocol (VoIP). Federal regulations do not consider the communication of VoIP telephony packets to be regulated as ordinary telephone services, provided that any voice communications are embedded in digital packets, as opposed to analog signals, at the point at which such voice communications leave a residence or customer premises using a network interface such as a user network interface (UNI). In such a manner, telephone calls conducted using the plain old telephone system (POTS) are subject to regulation by the federal government because of the use of an analog signal communicated over a twisted pair connection that carries voice traffic away from a residence or customer premises. Digital telephony protocols such as VoIP convert an analog signal from a handset or other client device into a digital packet, therefore providing that all voice communications leave a residence or customer premises in packetized form.
Traditional analog telephones that communicate voice traffic over a POTS network do so via a twisted pair, which is typically composed of two copper wires. Notably, telephones utilizing such twisted pair connections that do not include additional functionality such as an answering machine may not need an additional external power supply such as a battery or connection to a typical A/C power outlet. Instead, the functionality provided by such a POTS telephone set can be powered directly over the twisted pair connection via a talk battery and ringing signaling. In such a manner, a remote power supply located at a telephone company's facility, such as a central office or switching station, may be utilized to power telephones in remote residences and office buildings. Such telephones are typically referred to as being “line powered.”
One benefit to such telephones being line powered is less of a susceptibility to power outages that may be caused by an interruption in a power grid, natural disaster, or other power outage. While the power supply at the telephone company's central office or switching facility may also be susceptible to sources of power outages, such facilities may have greater protection from such power outages due to location, backup or emergency power sources, connection to a more centralized portion of a power grid, redundant connections to a power grid, or other enhanced ability to avoid power outages which may affect ordinary residences or businesses.
Another benefit of the invention is the improved economics of consolidating the costly ancillary signaling functions into a single location capable of serving multiple users. This reduces the cost of the user network device, and generally improves the cost per customer service impacts associated with service churn.
One disadvantage of digital telephones utilized, for example, to provide VoIP services is that they typically require a local power source such as an A/C wall outlet and are not “line powered” using a twisted pair or other connection. Such local power supply makes them more susceptible to power outages. Such telephones are typically equipped with an additional battery to allow the telephone to continue to function during short power outages wherein power from an A/C outlet may be unavailable.